Methods for depositing a transition metal chalcogenide film on a substrate by a cyclical deposition process

ABSTRACT

Systems for depositing a transition metal chalcogenide film on a substrate by cyclical deposition process are disclosed. The methods may include, contacting the substrate with at least one transition metal containing vapor phase reactant comprising at least one of a hafnium precursor, or a zirconium precursor, and contacting the substrate with at least one chalcogen containing vapor phase reactant. Semiconductor device structures including a transition metal chalcogenide film deposited by the methods of the disclosure are also provided.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of, and claims priority to, U.S.patent application Ser. No. 16/193,789 filed Nov. 16, 2018 titledMETHODS FOR DEPOSITING A TRANSITION METAL CHALCOGENIDE FILM ON ASUBSTRATE BY A CYCLICAL DEPOSITION PROCESS, the disclosure of which ishereby incorporated by reference in its entirety.

PARTIES OF JOINT RESEARCH AGREEMENT

The invention claimed herein was made by, or on behalf of, and/or inconnection with a joint research agreement between the University ofHelsinki and ASM Microchemistry Oy. The agreement was in effect on andbefore the date the claimed invention was made, and the claimedinvention was made as a result of activities undertaken within the scopeof the agreement.

FIELD OF INVENTION

The present disclosure relates generally to methods for depositing atransition metal chalcogenide film on a substrate by a cyclicaldeposition process and in particular to the cyclical deposition oftransition metal chalcogenides comprising hafnium or zirconium. Thedisclosure also relates to semiconductor device structures including atransition metal chalcogenide film deposited by a cyclical depositionprocess.

BACKGROUND OF THE DISCLOSURE

The interest in two-dimensional (2D) materials has increaseddramatically in recent years due to their potential in improvingperformance in next generation electronic devices. For example, graphenehas been the most studied 2D material to date and exhibits highmobility, transmittance, mechanical strength, and flexibility. However,the lack of a band gap in pure graphene has limited its performance insemiconductor device structures, such as transistors. Such limitationsin graphene have stimulated research in alternative 2D materials asanalogues of graphene. Recently, transition metal chalcogenides, andparticularly transition metal dichalcogenides, have attractedconsiderable research attention as an alternative to graphene.Transition metal dichalcogenides may have stoichiometry of MX₂, whichdescribes a transition metal (M) sandwiched between two layers ofchalcogen atoms (X), with strong in-plane covalent bonding between themetal-chalcogen and weak out-of-plane van der Waals bonding between thelayers.

However, there are few scalable, low temperature methods to produce 2Dmaterials. Currently, mechanical exfoliation of bulk crystals is themost commonly used method of formation, but although this methodproduces good quality crystals, the method is unable to producecontinuous films and is very labor intensive, making such a method notviable for industrial production. Chemical vapor deposition (CVD) hasbeen used to deposit 2D materials, but current CVD processes for somemetal chalcogenides, such as, for example, hafnium disulfide (HfS₂),operate at temperatures between 900° C. and 1000° C. and are unable toproduce continuous, large area 2D materials.

Accordingly, methods are desirable that are capable of producing 2Dmaterials, at a reduced deposition temperature, and with atomic levelfilm thickness control.

SUMMARY OF THE DISCLOSURE

This summary is provided to introduce a selection of concepts in asimplified form. These concepts are described in further detail in thedetailed description of example embodiments of the disclosure below.This summary is not intended to identify key features or essentialfeatures of the claimed subject matter, nor is it intended to be used tolimit the scope of the claimed subject matter.

In some embodiments, methods for depositing a transition metalchalcogenide film on a substrate by a cyclical deposition process areprovided. The methods may comprise: contacting the substrate with atleast one transition metal containing vapor phase reactant comprising atleast one of a hafnium precursor, or a zirconium precursor; andcontacting the substrate with at least one chalcogen containing vaporphase reactant, wherein the temperature of the substrate during thecontacting steps is below about 450° C.

The embodiments of the disclosure also provide semiconductor devicestructures comprising a transition metal chalcogenide film deposited bythe methods described herein.

For the purpose of summarizing the invention and the advantages achievedover the prior art, certain objects and advantages of the invention havebeen described herein above. Of course, it is to be understood that notnecessarily all such objects or advantages may be achieved in accordancewith any particular embodiment of the invention. Thus, for example,those skilled in the art will recognize that the invention may beembodied or carried out in a manner that achieves or optimizes oneadvantage or group of advantages as taught or suggested herein withoutnecessarily achieving other objects or advantages as may be taught orsuggested herein.

All of these embodiments are intended to be within the scope of theinvention herein disclosed. These and other embodiments will becomereadily apparent to those skilled in the art from the following detaileddescription of certain embodiments having reference to the attachedfigures, the invention not being limited to any particular embodiment(s)disclosed.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

While the specification concludes with claims particularly pointing outand distinctly claiming what are regarded as embodiments of theinvention, the advantages of embodiments of the disclosure may be morereadily ascertained from the description of certain examples of theembodiments of the disclosure when read in conjunction with theaccompanying drawings, in which:

FIG. 1 is a process flow diagram illustrating an exemplary cyclicaldeposition method according to the embodiments of the disclosure;

FIG. 2 illustrates the growth rate, crystallinity, and composition ofexemplary hafnium chalcogenide films deposited at various depositiontemperatures according to the embodiments of the disclosure;

FIG. 3 illustrates the growth rate, crystallinity, and composition ofexemplary zirconium chalcogenide films deposited at various depositiontemperatures according to the embodiments of the disclosure;

FIG. 4 illustrates grazing incidence x-ray diffraction (GIXRD) data forexemplary hafnium chalcogenide films deposited at various depositiontemperatures according to the embodiments of the disclosure;

FIG. 5 illustrates grazing incidence x-ray diffraction (GIXRD) data forexemplary zirconium chalcogenide films deposited at various depositiontemperatures according to the embodiments of the disclosure;

FIG. 6 illustrates the ambient stability over time of both a barezirconium chalcogenide film and a zirconium chalcogenide film cappedwith a metal silicate capping layer according to the embodiments of thedisclosure;

FIG. 7A illustrates grazing incidence x-ray diffraction (GIXRD) data forexemplary zirconium chalcogenide films deposited utilizing a differentnumber of deposition cycles without a capping layer deposited over thechalcogenide film according to the embodiments of the disclosure;

FIG. 7B illustrates grazing incidence x-ray diffraction (GIXRD) data forexemplary zirconium chalcogenide films deposited utilizing a differentnumber of deposition cycles with a capping layer deposited over thechalcogenide film according to the embodiments of the disclosure;

FIG. 8 illustrates an exemplary semiconductor device structure includinga transition metal chalcogenide film deposited according to theembodiments of the disclosure; and

FIG. 9 illustrates an exemplary reaction system which may be utilized todeposit a transition metal chalcogenide film according to theembodiments of the disclosure.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Although certain embodiments and examples are disclosed below, it willbe understood by those in the art that the invention extends beyond thespecifically disclosed embodiments and/or uses of the invention andobvious modifications and equivalents thereof. Thus, it is intended thatthe scope of the invention disclosed should not be limited by theparticular disclosed embodiments described below.

The illustrations presented herein are not meant to be actual views ofany particular material, structure, or device, but are merely idealizedrepresentations that are used to describe embodiments of the disclosure.

As used herein, the term “substrate” may refer to any underlyingmaterial or materials that may be used, or upon which, a device, acircuit or a film may be formed.

As used herein, the term “cyclic deposition” may refer to the sequentialintroduction of precursors (reactants) into a reaction chamber todeposit a film over a substrate and includes deposition techniques suchas atomic layer deposition and cyclical chemical vapor deposition.

As used herein, the term “atomic layer deposition” (ALD) may refer to avapor deposition process in which deposition cycles, preferably aplurality of consecutive deposition cycles, are conducted in a processchamber. Typically, during each cycle the precursor is chemisorbed to adeposition surface (e.g., a substrate surface or a previously depositedunderlying surface such as material from a previous ALD cycle), forminga monolayer or sub-monolayer that does not readily react with additionalprecursor (i.e., a self-limiting reaction). Thereafter, if necessary, areactant (e.g., another precursor or reaction gas) may subsequently beintroduced into the process chamber for use in converting thechemisorbed precursor to the desired material on the deposition surface.Typically, this reactant is capable of further reaction with theprecursor. Further, purging steps may also be utilized during each cycleto remove excess precursor from the process chamber and/or remove excessreactant and/or reaction byproducts from the process chamber afterconversion of the chemisorbed precursor. Further, the term “atomic layerdeposition,” as used herein, is also meant to include processesdesignated by related terms, such as chemical vapor atomic layerdeposition, atomic layer epitaxy (ALE), molecular beam epitaxy (MBE),gas source MBE, or organometallic MBE, and chemical beam epitaxy whenperformed with alternating pulses of precursor composition(s), reactivegas, and purge (e.g., inert carrier) gas.

As used herein, the term “cyclical chemical vapor deposition” may referto any process wherein a substrate is sequentially exposed to two ormore volatile precursors, which react and/or decompose on a substrate toproduce a desired deposition.

As used herein, the term “chalcogen containing vapor phase reactant” mayrefer to a reactant (precursor) containing a chalcogen, wherein achalcogen is an element from Group VI of the periodic table includingsulfur, selenium, and tellurium.

As used herein, the term “film” and “thin film” may refer to anycontinuous or non-continuous structures and material deposited by themethods disclosed herein. For example, “film” and “thin film” couldinclude 2D materials, nanolaminates, nanorods, nanotubes, ornanoparticles or even partial or full molecular layers or partial orfull atomic layers or clusters of atoms and/or molecules. “Film” and“thin film” may comprise material or a layer with pinholes, but still beat least partially continuous.

As used herein, the term “2D material” or “two-dimensional material” mayrefer to a nanometer scale crystalline material one, two or three atomsin thickness. In addition, “2D materials” or “two-dimensional material”may also refer to an ordered nanometer scale crystalline structurecomposed of multiple monolayers of crystalline materials ofapproximately three atoms in thickness per monolayer.

As used herein, the term “halide precursor” may refer to a transitionmetal halide precursor comprising a halide component including at leastone of chlorine, iodine, or bromine.

As used herein, the term “metalorganic precursor” may refer to atransition metal metalorganic precursor wherein “metalorganic” or“organometallic” are used interchangeably and may refer to organiccompounds containing a metal species. Organometallic compounds may beconsidered to be subclass of metalorganic compounds having directmetal-carbon bonds.

A number of example materials are given throughout the embodiments ofthe current disclosure; it should be noted that the chemical formulasgiven for each of the example materials should not be construed aslimiting and that the non-limiting example materials given should not belimited by a given example stoichiometry.

The embodiments of the disclosure may include methods for depositing atransition metal chalcogenide on a substrate by a cyclical depositionprocess and particularly methods for depositing transition metalchalcogenide films comprising either a hafnium component or a zirconiumcomponent by atomic layer deposition processes. As non-limitingexamples, hafnium disulfide (HfS₂) and zirconium disulfide (ZrS₂) areemerging materials, which have a 2D crystal structure, similar to thewell-known transition metal dichalcogenides (TMDCs), such as, forexample, molybdenum disulfide (MoS₂). In comparison to the most studied2D material, graphene, hafnium disulfide and zirconium disulfide mayhave a sizable band gap, which makes such exemplary transition metalchalcogenide films more suitable in semiconductor device structures,such as, for example, field effect transistors (FETs).

Current methods for forming transition metal chalcogenide films are notsuitable for forming high quality, conformal, low temperature thinfilms. Transition metal chalcogenide crystals may be formed bymechanical exfoliation of a bulk transition metal chalcogenide crystal,but such methods are not suitable for forming transition metalchalcogenide films to a thickness accuracy on the atomic scale onsuitable substrates. In addition, chemical vapor deposition of sometransition metal chalcogenide films has been demonstrated but suchprocesses operate at high deposition temperatures (e.g., greater than900° C. for HfS₂) and are unsuitable to produce nanoscale, conformal,thin films.

Cyclical deposition methods, such as cyclical chemical vapor depositionand atomic layer deposition techniques, are inherently scalable andoffer atomically accurate film thickness control, which is crucial inthe deposition of high quality 2D materials. In addition, cyclicdeposition methods with surface control in reactions, such as atomiclayer deposition, are characteristically conformal, thereby providingthe ability to uniformly coat three dimensional structures.

In addition, transition metal chalcogenide films may be susceptible tooxidation either during the deposition process or when exposed toambient conditions. Therefore cyclical deposition methods may bedesirable, which do not incorporate transition metal oxide phases intothe chalcogenide film during deposition. In addition, methods are highlydesirable to prevent the oxidation of the transition metal chalcogenidefilms when exposed to ambient conditions.

Accordingly, methods are desired which are capable of depositingtransition metal chalcogenide films at reduced temperatures,conformally, and with atomic thickness accuracy. In addition,semiconductor device structures comprising a transition metalchalcogenide film are desirable.

A non-limiting example embodiment of a cyclical deposition process mayinclude ALD, wherein ALD is based on typically self-limiting reactions,whereby sequential and alternating pulses of reactants are used todeposit about one atomic (or molecular) monolayer of material perdeposition cycle. The deposition conditions and precursors are typicallyselected to provide self-saturating reactions, such that an adsorbedlayer of one reactant leaves a surface termination that is non-reactivewith the vapor phase reactants of the same reactant. The substrate issubsequently contacted with a different reactant that reacts with theprevious termination to enable continued deposition. Thus, each cycle ofalternating pulsed reactants typically leaves no more than about onemonolayer of the desired material. However, as mentioned above, theskilled artisan will recognize that in one or more ALD cycles more thanone monolayer of material may be deposited, for example, if some gasphase reactions occur despite the alternating nature of the process.

In an ALD-type process for depositing a transition metal chalcogenidefilm, one deposition cycle may comprise exposing the substrate to afirst vapor phase reactant, removing any unreacted first reactant andreaction byproducts from the reaction space, and exposing the substrateto a second vapor phase reactant, followed by a second removal step. Thefirst reactant may comprise a transition metal containing precursor,such as a hafnium precursor or a zirconium precursor, and the secondreactant may comprise a chalcogen containing precursor.

Precursors may be separated by inert gases, such as argon (Ar), ornitrogen (N₂), to prevent gas phase reactions between reactants andenable self-saturating surface reactions. In some embodiments, however,the substrate may be moved to separately contact a first vapor phasereactant and a second vapor phase reactant. Because the reactionsself-saturate, strict temperature control of the substrates and precisedosage control of the precursor may not be required. However, thesubstrate temperature is preferably such that an incident gas speciesdoes not condense into monolayers nor decompose on the substratesurface. Surplus chemicals and reaction byproducts, if any, are removedfrom the substrate surface, such as by purging the reaction space or bymoving the substrate, before the substrate is contacted with the nextreactive chemical. Undesired gaseous molecules can be effectivelyexpelled from the reaction space with the help of an inert purging gas.A vacuum pump may be used to assist in the purging process.

Reactors capable of being used to deposit or grow thin films can be usedfor the deposition. Such reactors include ALD reactors, as well as CVDreactors equipped with appropriate equipment and means for providing theprecursors. According to some embodiments, a showerhead reactor may beused. In some embodiments the reactor is a spatial ALD reactor, in whichthe substrates moves or rotates during processing.

In some embodiments a batch reactor may be used. In some embodiments, avertical batch reactor is utilized in which the boat rotates duringprocessing. Thus, in some embodiments, the wafers rotate duringprocessing. In other embodiments, the batch reactor comprises amini-batch reactor configured to accommodate 10 or fewer wafers, 8 orfewer wafers, 6 or fewer wafers, 4 or fewer wafers, or 2 wafers. In someembodiments in which a batch reactor is used, wafer-to-wafernon-uniformity is less than 3% (1 sigma), less than 2%, less than 1% oreven less than 0.5%.

The deposition processes described herein can optionally be carried outin a reactor or reaction chamber connected to a cluster tool. In acluster tool, because each reaction chamber is dedicated to one type ofprocess, the temperature of the reaction chamber in each module can bekept constant, which improves the throughput compared to a reactor inwhich the substrate is heated up to the process temperature before eachrun. Additionally, in a cluster tool it is possible to reduce the timeto pump the reaction space to the desired process pressure levelsbetween substrates.

A stand-alone reactor can be equipped with a load-lock. In that case, itis not necessary to cool down the reaction chamber between each run. Insome embodiments, a deposition process for depositing a film comprisinga transition metal chalcogenide film may comprise a plurality ofdeposition cycles, for example ALD cycles.

In some embodiments, cyclical deposition processes are used to deposittransition metal chalcogenide thin films on a substrate and the cyclicaldeposition process may be an ALD type process. In some embodiments, thecyclical deposition may be a hybrid ALD/CVD or cyclical CVD process. Forexample, in some embodiments the deposition rate of the ALD process maybe low compared with a CVD process. One approach to increase thedeposition rate may be that of operating at a higher substratetemperature than that typically employed in an ALD process, resulting ina chemical vapor deposition process, but still taking advantage of thesequential introduction of precursors, such a process may be referred toas cyclical CVD. In some embodiments, a cyclical CVD process maycomprise the introduction of two or more precursors into the reactionchamber wherein there may be a time period of overlap between the two ormore precursors in the reaction chamber resulting in both an ALDcomponent of the deposition and a CVD component of the deposition. Forexample, a cyclical CVD process may comprise the continuous flow of afirst precursor and the periodic pulsing of a second precursor into thereaction chamber.

According to some embodiments of the disclosure, ALD processes are usedto deposit transition metal chalcogenide films on a substrate, such asan integrated circuit workpiece. In some embodiments, each ALD cycle maycomprise two distinct deposition steps or phases. In a first phase ofthe deposition cycle (“the metal phase”), the substrate surface on whichdeposition is desired is contacted with a first vapor phase reactantcomprising at least one of a hafnium precursor, or zirconium precursor,which chemisorbs onto the substrate surface, forming no more than aboutone monolayer of reactant species on the surface of the substrate. In asecond phase of the deposition cycle (“the chalcogen phase”), thesubstrate surface on which deposition is desired is contacted with asecond vapor phase reactant comprising at least one chalcogen containingvapor phase reactant which reacts with the previously chemisorbedspecies to form a transition metal chalcogenide film.

In some embodiments of the disclosure, the transition metal containingvapor phase reactant comprises at least one of a hafnium precursor, or azirconium precursor. In some embodiments, the hafnium precursor, or thezirconium precursor, comprises at least one of a halide precursor, or ametalorganic precursor. In some embodiments, the metalorganic precursormay comprise at least one of an alkylamide precursor, or acyclopentadienyl-ligand containing precursor. In some embodiments, thehafnium precursor, or zirconium precursor, may comprise a heterolepticprecursor.

In some embodiments, the hafnium precursor may comprise at least one ofa hafnium halide precursor, a hafnium metalorganic precursor, or anorganometallic hafnium precursor.

In some embodiments, the hafnium halide precursor may comprise at leastone halide ligand while the rest of the ligands are different, such asmetalorganic or organometallic ligands as described later herein. Insome embodiments, the hafnium halide precursor may comprise one, two,three or four halide ligands such as chloride ligands.

In some embodiments, the hafnium halide precursor may comprise at leastone of a hafnium chloride, a hafnium iodide, or a hafnium bromide. Insome embodiments, the hafnium chloride may comprise hafniumtetrachloride (HfCl₄). In some embodiments, the hafnium iodide maycomprise hafnium tetraiodide (HfI₄). In some embodiments, the hafniumbromide may comprise hafnium tetrabromide (HfBr₄).

In some embodiments, the hafnium metalorganic precursor may comprise atleast one of a hafnium alkylamide precursor, a hafniumcyclopentadienyl-ligand containing precursor, or other metalorganichafnium precursors.

In some embodiments, the hafnium alkylamide precursor may be selectedfrom the group comprising tetrakis(ethylmethylamido)hafnium(Hf(NEtMe)₄), tetrakis(dimethylamido)hafnium (Hf(NMe₂)₄), ortetrakis(diethylamido)hafnium (Hf(NEt₂)₄).

In some embodiments of the disclosure, the hafniumcyclopentadienyl-ligand containing precursor may be selected from thegroup comprising (tris(alkylamido)cyclopentadienylhafnium, such as(tris(dimethylamido)cyclopentadienylhafnium HfCp(NMe₂)₃, orbis(methylcyclopentadienyl)methoxymethyl hafnium (MeCp)₂Hf(CH)₃(OCH₃) orderivatives of those, such as ones in which there is one or morehydrocarbons, such as alkyls, attached to the cyclopentadienyl-ligand ofthose precursors, or other alkyl groups in alkylamido-ligand.

In some embodiments, the hafnium precursor may have the formula;HfL₁L₂L₃L₄wherein each of the L ligands through L1-L4 can be independentlyselected to be

-   -   a) Halide, such as chloride, bromide or iodide    -   b) Alkylamido, such as dimethylamido (—NMe₂), diethylamido        (—NEt₂), ethylmethylamido (—NEtMe)    -   c) Amidinate, such as N,N′-dimethylformamidinate    -   d) Guanidinate, such as        N,N′-diisopropyl-2-ethylmethylamidoguanidinate    -   e) Cyclopentadienyl or derivatives of those, such as        cyclopentadienyl or methylcyclopentadienyl or other        alkylsubstituted cyclopentadienyl ligands    -   f) Cycloheptadienyl or -trienyl-based, such as a        cycloheptatrienyl or cycloheptadienyl    -   g) Alkyl, such as C1-C5 alkyl, for example methyl, mostly in        case of heteroleptic precursors    -   h) Alkoxide, such as methoxide (—OMe), ethoxide (—OEt),        isopropoxide (—O^(i)Pr), n-butoxide (—OBu) or tert-butoxide        (—O^(t)Bu)    -   i) Betadiketonate, such as        (2,2,6,6-tetramethyl-3,5-heptanedionato) (thd)    -   j) Donor-functionalized alkoxide, such as dimethylethanolamine

In some embodiments of the disclosure, the hafnium precursor comprisesone or more bidentate ligands which are bonded to Hf through nitrogenand/or oxygen atoms. In some embodiments, the hafnium precursorcomprises one or more ligands which are bonded to Hf through nitrogen,oxygen, and/or carbon.

In some embodiments, the zirconium precursor may comprise at least oneof a zirconium halide precursor, a zirconium metalorganic precursor, oran organometallic zirconium precursor.

In some embodiments, the zirconium halide precursor may comprise atleast one of a zirconium chloride, a zirconium iodide, or a zirconiumbromide. In some embodiments, the zirconium chloride may comprisezirconium tetrachloride (ZrCl₄). In some embodiments, the zirconiumhalide precursor may comprise at least one halide ligand while the restof the ligands are different, such as metalorganic or organometallicligands as described later herein. In some embodiments, the zirconiumhalide precursor may comprise one, two, three or four halide ligandssuch as chloride ligands. In some embodiments, the zirconium iodide maycomprise zirconium tetraiodide (ZrI₄). In some embodiments, thezirconium bromide may comprise zirconium tetrabromide (ZrBr₄).

In some embodiments, the zirconium metalorganic precursor may compriseat least one of a zirconium alkylamide precursor, a zirconiumcyclopentadienyl-ligand containing precursor, or other metalorganiczirconium precursors.

In some embodiments, the zirconium alkylamide precursor may be selectedfrom the group comprising tetrakis(ethylmethylamido)zirconium(Zr(NEtMe)₄), tetrakis(dimethylamido)zirconium (Zr(NMe₂)₄), ortetrakis(diethylamido)zirconium (Zr(NEt₂)₄).

In some embodiments of the disclosure, the zirconiumcyclopentadienyl-ligand containing precursor may be selected from thegroup comprising (tris(alkylamido)cyclopentadienylzirconium, such as(tris(dimethylamido)cyclopentadienyl zirconium ZrCp(NMe₂)₃, orbis(methylcyclopentadienyl)methoxymethyl zirconium (MeCp)₂Zr(CH)₃(OCH₃),or derivatives of those, such as ones in which there is one or morehydrocarbons, such as alkyls, attached to the cyclopentadienyl-ligand ofthose precursors, or other alkyl groups in alkylamido-ligand.

In some embodiments, the zirconium precursor may have the formula;ZrL₁L₂L₃L₄

-   -   wherein each of the L ligands through L1-L4 can be independently        selected to be    -   k) Halide, such as chloride, bromide or iodide    -   l) Alkylamido, such as dimethylamido (—NMe₂), diethylamido        (—NEt₂), ethylmethylamido (—NEtMe)    -   m) Amidinate, such as N,N′-dimethylformamidinate    -   n) Guanidinate, such as        N,N′-diisopropyl-2-ethylmethylamidoguanidinate    -   o) Cyclopentadienyl or derivatives of those, such as        cyclopentadienyl or methylcyclopentadienyl or other        alkylsubstituted cyclopentadienyl ligands    -   p) Cycloheptadienyl or -trienyl-based, such as a        cycloheptatrienyl or cycloheptadienyl    -   q) Alkyl, such as C1-C5 alkyl, for example methyl, mostly in        case of heteroleptic precursors    -   r) Alkoxide, such as methoxide (—OMe), ethoxide (—OEt),        isopropoxide (—O^(i)Pr), n-butoxide (—OBu) or tert-butoxide        (—O^(t)Bu)    -   s) Betadiketonate, such as        (2,2,6,6-tetramethyl-3,5-heptanedionato) (thd)    -   t) Donor-functionalized alkoxide, such as dimethylethanolamine

In some embodiments of the disclosure, the zirconium precursor comprisesone or more bidentate ligands which are bonded to Zr through nitrogenand/or oxygen atoms. In some embodiments, the zirconium precursorcomprises one or more ligands which are bonded to Zr through nitrogen,oxygen, and/or carbon.

In some embodiments, exposing the substrate to the transition metalcontaining vapor phase reactant may comprise, pulsing the transitionmetal precursor over the substrate for a time period between about 0.01second and about 60 seconds, between about 0.05 seconds and about 10seconds, or between about 0.1 seconds and about 5.0 seconds. Inaddition, during the pulsing of the transition metal precursor over thesubstrate the flow rate of the transition metal precursor may be lessthan 2000 sccm, or less than 500 sccm, or even less than 100 sccm. Inaddition, during the pulsing of the transition metal precursor over thesubstrate the flow rate of the transition metal precursor may be fromabout 1 to about 2000 sccm, from about 5 to about 1000 sccm, or fromabout 10 to about 500 sccm.

In some embodiments, the purity of the transition metal containing vaporphase reactants may influence the composition of the deposited film andtherefore high purity sources of the transition metal containing vaporphase reactants may be utilized. For example, in some embodiments, thetransition metal vapor phase reactant may comprise a hafnium precursoror a zirconium precursor with a purity of greater than or equal to99.99%.

In some embodiments, the transition metal containing vapor phasereactant may be contained in a vessel and one or more heaters may beassociated with the vessel to control the temperature of the metalprecursor and subsequently the partial pressure of the metal precursor.In some embodiments of the disclosure, the metal precursor within thevessel may be heated to a temperature between approximately 20° C. andapproximately 300° C. For example, in some embodiments, the metalprecursor may be heated to a temperature from about 30° C. to about 250°C., or from about 40° C. to about 225° C., or from about 50° C. to about150° C., depending on the precursor choice.

In some embodiments, a vessel containing the metal precursor may beconnected to a source of one or more carrier gases. The carrier gas maybe introduced into the vessel and drawn over the surface of, or bubbledthrough, the metal precursor contained within the vessel. The resultingevaporation of the metal precursor causes a vapor of the metal precursorto become entrained in the carrier gas to thereby produce the transitionmetal vapor phase reactant which can be dispensed to a reaction chamber.

In some embodiments, in addition to utilizing high purity transitionmetal precursors, the carrier gas may be further purified to removeunwanted impurities. Therefore, some embodiments of the disclosure mayfurther comprise, flowing a carrier gas through a vessel containing asource of the transition metal containing vapor phase reactant totransport the transition metal containing vapor phase reactant to thereaction chamber. Further embodiments of the disclosure may comprise,flowing the carrier through a gas purifier prior to entering the sourceof the transition metal containing vapor phase reactant to reduce theconcentration of at least one of water, or oxygen, within the carriergas.

In some embodiments, the water concentration within the carrier gas maybe reduced to less than 10 parts per million, or less than 1 part permillion, or less than 100 parts per billion, or less than 10 parts perbillion, or less than 1 part per billion, or even less than 100 partsper trillion.

In some embodiments, the oxygen concentration within the carrier gas maybe reduced to 10 parts per million, or less than 1 part per million, orless than 100 parts per billion, or less than 10 parts per billion, orless than 1 part per billion, or even less than 100 parts per trillion.

In some embodiments, the hydrogen (H₂) concentration within the carriergas may be reduced to less than 100 parts per trillion. In someembodiments, the carbon dioxide (CO₂) concentration within the carriergas may be reduced to less than 100 parts per trillion. In someembodiments, the carbon monoxide (CO) concentration within the carriergas may be reduced to less than 100 parts per trillion.

In some embodiments, the carrier gas may comprise nitrogen gas (N₂) andthe carrier gas purifier may comprise a nitrogen gas purifier.

In some embodiments of the disclosure, the transition metal containingvapor phase reactant may be fed through a gas purifier prior to enteringthe reaction chamber in order to reduce the concentration of at leastone of water, or oxygen, within the transition metal containing vaporphase reactant.

In some embodiments, the water concentration within the transition metalcontaining vapor phase reactant may be reduced to less than 1 atomic-%,or less than 1000 parts per million, or less than 100 parts per million,or less than 10 parts per million, or less than 1 part per million, orless than 100 parts per billion, or even less than 100 parts pertrillion.

In some embodiments, the oxygen concentration within the transitionmetal containing vapor phase reactant may be reduced to less than 1atomic-%, or less than 1000 parts per million, or less than 100 partsper million, or less than 10 parts per million, or less than 1 part permillion, or less than 100 parts per billion, or even less than 100 partsper trillion.

Not to be bound be any theory or mechanism, but it is believed thereduction of at least one of the water concentrations, or the oxygenconcentration, within the carrier gas and/or the transition metalcontaining vapor phase reactant may allow for the deposition of atransition metal chalcogenide film with the desired composition whilstpreventing the deposition of transition metal oxide phases at anappropriate deposition temperature.

Excess transition metal vapor phase reactant, such as, for example, ahafnium precursor, or a zirconium precursor, and reaction byproducts (ifany) may be removed from the substrate surface, e.g., by pumping with aninert gas. For example, in some embodiments of the disclosure themethods may include a purge cycle wherein the substrate surface ispurged for a time period of less than approximately 5.0 seconds, or lessthan approximately 2.0 seconds, or even less than approximately 1.0second. In some embodiments, the substrate surface is purged for a timeperiod between about 0.01 seconds and about 60 seconds, or between about0.05 seconds and about 10 seconds, or between about 0.1 seconds andabout 5 seconds. Excess transition metal vapor phase reactant and anyreaction byproducts may be removed with the aid of a vacuum generated bya pumping system.

In a second phase of the deposition cycle (“the chalcogen phase”) thesubstrate is contacted with a second vapor phase reactant comprising atleast one chalcogen containing vapor phase reactant. In some embodimentsof the disclosure, the at least one chalcogenide containing vaporreactant may comprise hydrogen sulfide (H₂S), hydrogen selenide (H₂Se),dimethyl sulfide ((CH₃)₂S), or dimethyl telluride ((CH₃)₂Te).

It will be understood by one skilled in the art that any number ofchalcogen precursors may be used in the cyclical deposition processesdisclosed herein. In some embodiments, a chalcogen precursor is selectedfrom the following list: H₂S, H₂Se, H₂Te, (CH₃)₂S, (NH₄)₂S,dimethylsulfoxide ((CH₃)₂SO), (CH₃)₂Se, (CH₃)₂Te, elemental or atomic S,Se, Te, other precursors containing chalcogen-hydrogen bonds, such asH₂S₂, H₂Se₂, H₂Te₂, or chalcogenols with the formula R—Y—H, wherein Rcan be a substituted or unsubstituted hydrocarbon, preferably a C1-C8alkyl or substituted alkyl, such as an alkylsilyl group, more preferablya linear or branched C1-C5 alkyl group, and Y can be S, Se, or Te. Insome embodiments a chalcogen precursor is a thiol with the formulaR—S—H, wherein R can be substituted or unsubstituted hydrocarbon,preferably C1-C8 alkyl group, more linear or branched preferably C1-C5alkyl group. In some embodiments a chalcogen precursor has the formula(R₃Si)₂Y, wherein R₃Si is an alkylsilyl group and Y can be S, Se or Te.In some embodiments, a chalcogen precursor comprises S or Se. In someembodiments, a chalcogen precursor comprises S. In some embodiments, achalcogen precursor does not comprise S. In some embodiments thechalcogen precursor may comprise an elemental chalcogen, such aselemental sulfur. In some embodiments, a chalcogen precursor doescomprise Te. In some embodiments, a chalcogen precursor does notcomprise Te. In some embodiments, a chalcogen precursor does compriseSe. In some embodiments, a chalcogen precursor does not comprise Se. Insome embodiments, a chalcogen precursor is selected from precursorscomprising S, Se or Te. In some embodiments, a chalcogen precursorcomprises H₂S_(n), wherein n is from 4 to 10.

In some embodiments, suitable chalcogen precursors may include anynumber of chalcogen-containing compounds. In some embodiments, achalcogen precursor may comprise at least one chalcogen-hydrogen bond.In some embodiments the chalcogen precursor may comprise a chalcogenplasma, chalcogen atoms or chalcogen radicals. In some embodiments wherean energized chalcogen precursor is desired, a plasma may be generatedin the reaction chamber or upstream of the reaction chamber. In someembodiments the chalcogen precursor does not comprise an energizedchalcogen precursor, such as plasma, atoms or radicals. In someembodiments the chalcogen precursor may comprise a chalcogen plasma,chalcogen atoms or chalcogen radicals formed from a chalcogen precursorcomprising a chalcogen-hydrogen bond, such as H₂S. In some embodiments achalcogen precursor may comprise a chalcogen plasma, chalcogen atoms orchalcogen radicals such as a plasma comprising sulfur, selenium ortellurium, preferably a plasma comprising sulfur. In some embodiments,the plasma, atoms, or radicals comprise tellurium. In some embodiments,the plasma, atoms or radicals comprise selenium. In some embodiments thechalcogen precursor does not comprise a tellurium precursor.

In some embodiments, the purity of the chalcogen containing vapor phasereactants may influence the composition of the deposited film andtherefore high purity sources of the chalcogen containing vapor phasereactant may be utilized. In some embodiments, the chalcogen containingvapor phase reactant may have a purity of greater than or equal to99.5%. As a non-limiting example, the chalcogen containing vapor phasereactant may comprise hydrogen sulfide (H₂S) with a purity of greaterthan or equal to 99.5%.

In some embodiments, in addition to utilizing high purity chalcogencontaining vapor phase reactants, the chalcogen precursor gas may befurther purified to remove unwanted impurities. Therefore, someembodiments of the disclosure may further comprise, flowing a chalcogencontaining vapor phase reactant through a gas purifier prior to enteringthe reaction chamber to reduce the concentration of at least one ofwater, or oxygen, within the chalcogen containing vapor phase reactant.

In some embodiments, the water, or oxygen concentration within thechalcogen containing vapor phase reactant may be reduced to less than 5atomic-%, or less than 1 atomic-%, or less than 1000 parts per million,or less than 100 parts per million, or less than 10 parts per million,or less than 1 part per million, or less than 100 parts per billion, orless than 10 parts per billion, or even less than 1 part per billion.

Not to be bound be any theory or mechanism, but it is believed thereduction of at least one of the water concentration, or the oxygenconcentration within the chalcogen containing vapor phase reactant mayallow for the deposition of transition metal chalcogenide film with thedesired composition whilst preventing the deposition of transition metaloxide phases at an appropriate deposition temperature.

In some embodiments, exposing the substrate to the chalcogen containingvapor phase reactant may comprise, pulsing the chalcogen precursor(e.g., hydrogen sulfide) over the substrate for a time period of between0.1 seconds and 2.0 seconds, or from about 0.01 seconds to about 10seconds, or less than about 20 seconds, or less than about 10 seconds,or less than about 5 seconds. During the pulsing of the chalcogenprecursor over the substrate the flow rate of the chalcogen precursormay be less than 2000 sccm, or less than 500 sccm, or even less than 100sccm. In addition, during the pulsing of the chalcogen precursor overthe substrate the flow rate of the chalcogen precursor may be from about1 sccm to about 2000 sccm, or from about 5 sccm to about 1000 sccm, orfrom about 10 sccm to about 500 sccm.

The second vapor phase reactant comprising a chalcogen containingprecursor may react with the metal-containing molecules left on thesubstrate. In some embodiments, the second phase chalcogen precursor maycomprise hydrogen sulfide and the reaction may deposit a transitionmetal disulfide on the surface of the substrate.

Excess second source chemical and reaction byproducts, if any, may beremoved from the substrate surface, for example, by a purging gas pulseand/or vacuum generated by a pumping system. Purging gas is preferablyany inert gas, such as, without limitation, argon (Ar), nitrogen (N₂),or helium (He). A phase is generally considered to immediately followanother phase if a purge (i.e., purging gas pulse) or other reactantremoval step intervenes.

The deposition cycle in which the substrate is alternatively contactedwith the first vapor phase reactant (i.e., the transition metalcontaining precursor) and the second vapor phase reactant (i.e., thechalcogen containing precursor) may be repeated one or more times untila desired thickness of a transition metal chalcogenide is deposited. Itshould be appreciated that in some embodiments of the disclosure, theorder of the contacting of the substrate with the first vapor phasereactant and the second vapor phase reactant may be such that thesubstrate is first contacted with the second vapor phase reactantfollowed by the first vapor phase reactant. In addition, in someembodiments, the cyclical deposition process may comprise contacting thesubstrate with the first vapor phase reactant (i.e. the transition metalcontaining precursor) one or more times prior to contacting thesubstrate with the second vapor phase reactant (i.e., the chalcogencontaining precursor) one or more times and similarly may alternativelycomprise contacting the substrate with the second vapor phase reactantone or more times prior to contacting the substrate with the first vaporphase reactant one or more times.

In addition, some embodiments of the disclosure may comprise non-plasmareactants, e.g., the first and second vapor phase reactants aresubstantially free of ionized reactive species. In some embodiments, thefirst and second vapor phase reactants are substantially free of ionizedreactive species, excited species or radical species. For example, boththe first vapor phase reactant and the second vapor phase reactant maycomprise non-plasma reactants to prevent ionization damage to theunderlying substrate and the associated defects thereby created.

The cyclical deposition processes described herein, utilizing atransition metal containing precursor and a chalcogen containingprecursor to form a transition metal chalcogenide film, may be performedin an ALD or CVD deposition system with a heated substrate, i.e., thetemperature of the substrate during the process of contacting thesubstrate with the chemical precursors may be controlled.

For example, in some embodiments, methods may comprise heating thesubstrate to temperature of between approximately 200° C. andapproximately 500° C., or even heating the substrate to a temperature ofbetween approximately 350° C. and approximately 450° C. Of course, theappropriate temperature window for any given cyclical depositionprocess, such as for an ALD reaction, will depend upon the surfacetermination and reactant species involved. Here, the temperature variesdepending on the precursors being used and is generally at or belowabout 700° C. In some embodiments, the deposition temperature isgenerally at or above about 100° C. for vapor deposition processes. Insome embodiments the deposition temperature is between about 100° C. andabout 600° C., and in some embodiments the deposition temperature isbetween about 300° C. and about 500° C. In some embodiments thedeposition temperature is below about 500° C., or below about 475° C.,or below about 450° C., or below about 425° C. or below about 400° C.,or below about 375° C., or below about 350° C., or below about 325° C.or below about 300° C. In some instances the deposition temperature canbe below about 250° C., or below about 200° C., or below about 150° C.,or below about 100° C., for example, if additional reactants or reducingagents are used in the process. In some instances the depositiontemperature can be above about 20° C., above about 50° C. and aboveabout 75° C. In some embodiments of the disclosure, the depositiontemperature, i.e., the temperature of the substrate during deposition isapproximately 400° C.

In some embodiments the growth rate of the transition metal chalcogenidefilm is from about 0.005 Å/cycle to about 5 Å/cycle, or from about 0.01Å/cycle to about 2.0 Å/cycle. In some embodiments the growth rate of thefilm is more than about 0.05 Å/cycle, or more than about 0.1 Å/cycle, ormore than about 0.15 Å/cycle, or more than about 0.20 Å/cycle, or morethan about 0.25 Å/cycle, or even more than about 0.3 Å/cycle. In someembodiments the growth rate of the film is less than about 2.0 Å/cycle,or less than about 1.0 Å/cycle, or less than about 0.75 Å/cycle, or lessthan about 0.5 Å/cycle, or less than about 0.2 Å/cycle. In someembodiments of the disclosure, the growth rate of the transition metalchalcogenide is approximately 0.10 Å/cycle.

The embodiments of the disclosure may comprise a cyclical depositionprocess which may be illustrated in more detail by the exemplary method100 of FIG. 1. The exemplary method 100 may begin with a process block110 which comprises, providing a substrate into a reaction chamber andheating the substrate to the deposition temperature.

In some embodiments of the disclosure, the substrate may comprise aplanar substrate or a patterned substrate including high aspect ratiofeatures, such as, for example, trench structures and/or fin structures.The substrate may comprise one or more materials including, but notlimited to, silicon (Si), germanium (Ge), germanium tin (GeSn), silicongermanium (SiGe), silicon germanium tin (SiGeSn), silicon carbide (SiC),or a group III-V semiconductor material, such as, for example, galliumarsenide (GaAs), gallium phosphide (GaP), or gallium nitride (GaN). Insome embodiments, the substrate may comprise one or more dielectricmaterials including, but not limited to, oxides, nitrides, oroxynitrides. For example, the substrate may comprise a silicon oxide(e.g., SiO₂), a metal oxide (e.g., Al₂O₃), a silicon nitride (e.g.,Si₃N₄), or a silicon oxynitride. In some embodiments of the disclosure,the substrate may comprise an engineered substrate wherein a surfacesemiconductor layer is disposed over a bulk support with an interveningburied oxide (BOX) disposed there between.

Patterned substrates may comprise substrates that may includesemiconductor device structures formed into or onto a surface of thesubstrate, for example, a patterned substrate may comprise partiallyfabricated semiconductor device structures, such as, for example,transistors and/or memory elements. In some embodiments, the substratemay contain monocrystalline surfaces and/or one or more secondarysurfaces that may comprise a non-monocrystalline surface, such as apolycrystalline surface and/or an amorphous surface. Monocrystallinesurfaces may comprise, for example, one or more of silicon (Si), silicongermanium (SiGe), germanium tin (GeSn), germanium (Ge), or a III-Vmaterial. Polycrystalline or amorphous surfaces may include dielectricmaterials, such as oxides, oxynitrides, or nitrides, such as, forexample, silicon oxides and silicon nitrides.

The reaction chamber utilized for the exemplary cyclical depositionprocess 100 may be an atomic layer deposition reaction chamber, or achemical vapor deposition reaction chamber, or any of the reactionchambers as previously described herein. In some embodiments of thedisclosure, the reaction chamber may be subjected to a pre-annealingprocess prior to loading the substrate within the reaction chamber orwith the substrate pre-loaded into the reaction chamber. For example,the pre-annealing process may be utilized to reduce the concentration ofat least one of water, and/or oxygen, within the reaction chamber.Therefore, some embodiments of the disclosure may further comprise,pre-annealing the reaction chamber prior to film deposition attemperature of greater than 400° C., or greater than 500° C., or greaterthan 600° C., or even greater than 700° C. In some embodiments, thepre-annealing of the reaction chamber at high temperature may beperformed for time period of less than 60 minutes, or less than 30minutes, or less than 15 minutes, or less than 10 minutes, or even lessthan 5 minutes.

The process block 110 (of FIG. 1) may continue by heating the substrateto a desired deposition temperature, as previously disclosed herein. Asa non-limiting example, the substrate may be heated to depositiontemperature between approximately 300° C. and approximately 450° C., orto a temperature of approximately 400° C.

The exemplary method 100 may continue with cyclical deposition phase 140which may commence by means of a process block 120 which comprises,contacting the substrate with a transition metal containing vapor phasereactant, as previously disclosed herein. As a non-limiting example, thesubstrate may be contacted with hafnium tetrachloride (HfCl₄) orzirconium tetrachloride (ZrCl₄), for a time period of approximately 1second. Upon contacting the substrate with the transition metalcontaining precursor, the excess transition metal containing precursorand any byproducts may be removed from the reaction chamber by apurge/pump process.

The cyclical deposition phase 140 of the exemplary method 100 maycontinue by means of a process block 130 which comprises, contacting thesubstrate with a chalcogen containing vapor phase reactant, aspreviously disclosed herein. As a non-limiting example, the substratemay be contacted with hydrogen sulfide (H₂S) for a time period ofapproximately 1 second. Upon contacting the substrate with the chalcogencontaining precursor, the excess chalcogen containing precursor and anybyproducts may be removed from the reaction chamber by purge/pumpprocess.

The method wherein the substrate is alternately and sequentiallycontacted with at least one transition metal containing vapor phasereactant and contacted with at least one chalcogen containing vaporphase reactant may constitute one unit deposition cycle. For example, aunit deposition cycle may comprise, contacting substrate with thetransition metal vapor phase reactant, purging the reaction chamber,contacting the substrate with the chalcogen containing vapor phasereactant, and again purging the reaction chamber.

In some embodiments of the disclosure, the method of depositing atransition metal chalcogenide may comprise repeating the unit depositioncycle one or more times. For example, the cyclic deposition phase 140 ofexemplary method 100 may continue by means of a decision gate 150 whichdetermines if the cyclical deposition phase 140 of exemplary method 100continues or exits. The decision gate of the process block 150 may bedetermined based on the thickness of the transition metal chalcogenidefilm deposited. For example, if the thickness of the transition metalchalcogenide film is insufficient for the desired application, then thecyclical deposition phase 140 of the exemplary method 100 may return tothe process block 120 and the processes of contacting the substrate witha transition metal containing vapor phase reactant and contacting thesubstrate with a chalcogen containing vapor phase reactant may berepeated one or more times. Once the transition metal chalcogenide filmhas been deposited to a desired thickness the exemplary method 100 mayexit via a process block 160 and the transition metal chalcogenide filmmay be subjected to additional processes to form a device structure.

In some embodiments of the disclosure, the deposition temperature of thetransition metal chalcogenide film may affect the growth rate of thechalcogenide film, the crystallinity of the chalcogenide film, and thecomposition the chalcogenide film. As a non-limiting example, FIG. 2illustrates the growth rate, crystallinity, and composition, ofexemplary hafnium disulfide films deposited at various depositiontemperatures utilizing hafnium tetrachloride (HfCl₄) and hydrogensulfide (H₂S) as the precursor chemicals. Examination of FIG. 2illustrates that between a deposition temperature of approximately 200°C., up to a deposition of approximately 350° C., the deposition rate ofthe exemplary hafnium disulfide films decreases and the crystalstructure of the hafnium disulfide films is amorphous, i.e., there is nolong range ordering of the crystal structure which would normally beassociated with a crystalline material. Between a deposition temperatureof approximately 350° C. and approximately 400° C. there is an increasethe growth rate of the exemplary hafnium disulfide films and the crystalstructure of the hafnium disulfide films becomes crystalline, i.e.,there is long range ordering of the crystalline structure of thechalcogenide film. In addition, between a deposition temperature ofapproximately 350° C. and approximately 400° C., the exemplary hafniumdisulfide film exhibits a composition of hafnium disulfide (HfS₂).However, as the deposition temperature is further increased above atemperature of approximately 400° C., the growth rate of the exemplaryfilms again decreases and the composition of the deposited film becomesthat of a mixture between a hafnium sulfide and a hafnium oxide. Thedeposition of hafnium oxide phases above a temperature of approximately400° C. may result from residual oxygen and/or water remaining in thereaction chamber utilized in the above non-limiting examples. In furthernon-limiting examples, the residual oxygen and/or water concentrationwithin the reaction chamber may be further reduced and deposition abovea temperature of approximately 400° C. may result in deposition of ahafnium disulfide (HfS₂) film without the deposition of hafnium oxidephases.

Therefore, in some embodiments of the disclosure, the transition metalchalcogenide film may comprise a hafnium sulfide and particularlyhafnium disulfide (HfS₂). In addition, in some embodiments, thetransition metal chalcogenide film may be crystalline with a compositioncomprising hafnium disulfide (HfS₂) at a deposition temperature betweenapproximately 350° C. and approximately 400° C., and particular at adeposition temperature of approximately 400° C. In some embodiments, acrystalline hafnium disulfide (HfS₂) film may be deposited at adeposition temperature greater than 400° C.

As a further non-limiting example, FIG. 3 illustrates the growth rate,crystallinity, and composition, of exemplary zirconium sulfide filmsdeposited at various deposition temperatures utilizing zirconiumtetrachloride (ZrCl₄) and hydrogen sulfide (H₂S) as the precursorchemicals. Examination of FIG. 3 illustrates that between a depositiontemperature of approximately 200° C., up to a deposition ofapproximately 350° C., the deposition rate of the exemplary zirconiumsulfide films increases and the crystal structure of the zirconiumsulfide films is amorphous, i.e., there is no long range ordering in thecrystal structure which would normally be associated with a crystallinematerial. Between a deposition temperature of approximately 350° C. andapproximately 400° C. there is a further increase in the growth rate ofthe exemplary zirconium sulfide films and the crystal structure of thezirconium sulfide films becomes crystalline, i.e., there is long rangeordering of the crystalline structure of the chalcogenide film. Inaddition, between a deposition temperature of approximately 350° C. andapproximately 400° C., the exemplary zirconium sulfide film exhibits acomposition of zirconium disulfide (ZrS₂). However, as the depositiontemperature is further increased above a temperature of approximately400° C., the growth rate of the exemplary films initially decreases andthen again increases and the composition of the deposited film becomesthat of a mixture between a zirconium sulfide and a zirconium oxide. Thedeposition of zirconium oxide phases above a temperature ofapproximately 400° C. may result from residual oxygen and/or waterremaining in the reaction chamber utilized in the above non-limitingexamples. In further non-limiting examples, the residual oxygen and/orwater concentration within the reaction chamber may be further reducedand deposition above a temperature of approximately 400° C. may resultin deposition of a zirconium disulfide (ZrS₂) film without thedeposition of zirconium oxide phases.

Therefore, in some embodiments of the disclosure, the transition metalchalcogenide film may comprise a zirconium sulfide and particularlyzirconium disulfide (ZrS₂). In addition, in some embodiments, thetransition metal chalcogenide film may be crystalline with a compositioncomprising zirconium disulfide (ZrS₂) at a deposition temperaturebetween approximately 350° C. and approximately 400° C., and particularat a deposition temperature of approximately 400° C. In someembodiments, a crystalline zirconium disulfide (ZrS₂) film may bedeposited at a deposition temperature greater than 400° C.

As further non-limiting examples of the transition metal chalcogenidefilms deposited according to the embodiments of the disclosure, FIG. 4and FIG. 5 illustrate grazing incidence x-ray diffraction (GIXRD) datafor hafnium sulfide films deposited utilizing hafnium tetrachloride(HfCl₄) and hydrogen sulfide (H₂S) as chemical precursor (FIG. 4) andzirconium sulfide films deposited utilizing zirconium tetrachloride(ZrCl₄) and hydrogen sulfide (H₂S) as chemical precursors (FIG. 5)deposited at various deposition temperature between 200° C. and 500° C.

Examination of FIG. 4 illustrates that for a deposition temperature of200° C., up to a deposition temperature of 350° C., the GIXRD data doesnot include any discernable peaks in the data, corresponding to anon-crystalline film, i.e., the exemplary hafnium sulfide films areamorphous. For a deposition temperature of 400° C., up to a depositiontemperature of 450° C., the GIXRD data has a discernable primary peakcorresponding to a crystalline hafnium sulfide film and in particular ahafnium disulfide film with a composition (HfS₂). In addition, for adeposition temperature between 400° C. and 450° C. the exemplary hafniumdisulfide films have a predominate (001) crystallographic orientation asdemonstrated by the location of the peak in the GIXRD data. For adeposition temperature of 500° C. the peak in the GIXRD data related tohafnium disulfide is not discernable but rather a number of smallerpeaks corresponding to a hafnium oxide (e.g., HfO₂) are presentindicating the deposited film comprises a hafnium oxide film. Aspreviously described herein, the presence of hafnium oxide phases at adeposition of 500° C. may be due to residual water and/or oxygen withinthe reaction chamber utilized to deposit the exemplary hafnium sulfidefilms of FIG. 4. In additional non-limiting examples, the reactionchamber utilized to deposit the hafnium sulfide films may have a reducedconcentration of water and/or oxygen and deposition at a temperature of500° C. and above may result in crystalline hafnium sulfide filmswithout the presence of hafnium oxide phases.

Therefore, in some embodiments of the disclosure, the transition metalchalcogenide film may comprise a hafnium sulfide and particularlyhafnium disulfide (HfS₂). In addition, in some embodiments, thetransition metal chalcogenide film may comprise crystalline hafniumdisulfide (HfS₂) with a predominant (001) crystallographic orientationfor a deposition temperature between approximately 350° C. andapproximately 400° C., and particular at a deposition temperature ofapproximately 400° C. In some embodiments, the transition metalchalcogenide film may comprise crystalline hafnium disulfide (HfS₂) witha predominant (001) crystallographic orientation for a depositiontemperature greater than 400° C.

In addition, GIXRD data from exemplary zirconium sulfide films areillustrated in FIG. 5 and examination of FIG. 5 illustrates that for adeposition temperature of 200° C., up to a deposition temperature of300° C., the GIXRD data does not include any discernable peaks in thedata, corresponding to a non-crystalline film, i.e., the exemplaryzirconium sulfide films are amorphous. For a deposition temperature of350° C., up to a deposition temperature of 450° C., the GIXRD data has asingle discernable peak corresponding to a crystalline zirconium sulfidefilm and in particular a zirconium disulfide film with a composition(ZrS₂). In addition, for a deposition temperature between 350° C. and450° C. the exemplary zirconium disulfide films have a predominate (001)crystallographic orientation as demonstrated by the location of the peakin the GIXRD data. For a deposition temperature of 500° C. the peak inthe GIXRD data related to zirconium disulfide is present but also anumber of smaller peaks corresponding to a zirconium oxide (e.g., ZrO₂)are present indicating the deposited film comprises a mixture of both azirconium sulfide and a zirconium oxide. As previously described herein,the presence of zirconium oxide phases at a deposition temperature of500° C. may be due to residual water and/or oxygen within the reactionchamber utilized to deposit the exemplary zirconium sulfide films ofFIG. 5. In additional non-limiting examples, the reaction chamberutilized to deposit the zirconium sulfide films may have a reducedconcentration of water and/or oxygen and deposition at a temperature of500° C. and above may result in crystalline zirconium sulfide filmswithout the presence of zirconium oxide phases.

Therefore, in some embodiments of the disclosure, the transition metalchalcogenide film may comprise a zirconium sulfide and a particularlyzirconium disulfide (ZrS₂). In addition, in some embodiments, thetransition metal chalcogenide film may comprise crystalline zirconiumdisulfide (ZrS₂) with a (001) crystallographic orientation for adeposition temperature between approximately 300° C. and approximately450° C., and particular at a deposition temperature of approximately400° C. In some embodiments, the transition metal chalcogenide film maycomprise crystalline zirconium disulfide (ZrS₂) with a predominant (001)crystallographic orientation for a deposition temperature of greaterthan 400° C.

In some embodiments of the disclosure, the as-deposited transition metalchalcogenide films may be subjected to a post-deposition annealingprocess to improve the crystallinity of the transition metalchalcogenide thin films. For example, in some embodiments, the method ofdepositing the transition metal chalcogenide film may further comprise,a post-deposition annealing of the metal chalcogenide at a temperatureabove the deposition temperature of the transition metal chalcogenidefilm. For example, in some embodiments, annealing of the transitionmetal chalcogenide may comprise, heating the transition metalchalcogenide film to a temperature of approximately less than 800° C.,or approximately less than 600° C., or approximately less than 500° C.,or even approximately less than 400° C. In some embodiments, thepost-deposition annealing of the transition metal chalcogenide thin filmmay be performed in an atmosphere comprising a chalcogen, for example,the post-deposition annealing process may be performed in an ambientcomprising a chalcogenide compound, for example sulfur compounds, suchas a hydrogen sulfide (H₂S) atmosphere. In some embodiments, thepost-deposition annealing of the metal chalcogenide thin film may beperformed for a time period of less than 1 hour, or less than 30minutes, or less than 15 minutes, or even less than 5 minutes. In someembodiments, the post-deposition annealing of the transition metalchalcogenide thin film may be performed in an atmosphere not comprisingchalcogens, such as S, Se, or Te, for example, in inert gas ambient suchas N₂, or noble gas, such as Ar or He, or in hydrogen containing ambientsuch as H₂ or H₂/N₂ ambient.

Transition metal chalcogenide films, such as, for example, hafniumdisulfide and zirconium disulfide films, deposited according to some ofthe embodiments of the disclosure may be continuous films comprising a2D material. In some embodiments the films comprising a transition metalchalcogenide film deposited according to some of the embodimentsdisclosure may be continuous at a thickness below about 100 nanometers,or below about 60 nanometers, or below about 50 nanometers, or belowabout 40 nanometers, or below about 30 nanometers, or below about 25nanometers, or below about 20 nanometers, or below about 15 nanometers,or below about 10 nanometers, or below about 5 nanometers or lower.

In some embodiments, the transition metal chalcogenide films depositedaccording to the embodiments of the disclosure may be continuous over asubstrate having a diameter greater than 100 millimeters, or greaterthan 200 millimeters, or greater than 300 millimeters, or even greaterthan 400 millimeters. The continuity referred to herein can be physicalcontinuity or electrical continuity. In some embodiments the thicknessat which a film may be physically continuous may not be the same as thethickness at which a film is electrically continuous, and the thicknessat which a film may be electrically continuous may not be the same asthe thickness at which a film is physically continuous.

In some embodiments of the disclosure, the transition metal chalcogenidefilms deposited by the methods disclosed herein may comprise at leastone of a hafnium sulfide, a hafnium selenide, a hafnium telluride, azirconium sulfide, a zirconium selenide, or a zirconium telluride.

In some embodiments of the disclosure, the transition metal chalcogenidefilms deposited by the methods disclosed herein may comprise a hafniumchalcogenide and particularly a hafnium sulfide having the generalformula HfS_(x), wherein x may range from approximately 0.75 toapproximately 2.8, or wherein x may range from approximately 0.8 toapproximately 2.5, or wherein x may range from 0.9 to approximately 2.3,or alternatively wherein x may range from approximately 0.95 toapproximately 2.2. The elemental composition ranges for HfS_(x) maycomprise Hf from about 30 atomic % to about 60 atomic %, or from about35 atomic % to about 55 atomic %, or even from about 40 atomic % toabout 50 atomic %. Alternatively the elemental composition ranges forHfS_(x) may comprise S from about 25 atomic % to about 75 atomic %, or Sfrom about 30 atomic % to about 60 atomic %, or even S from about 35atomic % to about 55 atomic %.

In some embodiments of the disclosure, the transition metal chalcogenidefilms deposited by the methods disclosed herein may comprise a zirconiumchalcogenide and particularly a zirconium sulfide having the generalformula ZrS_(x), wherein x may range from approximately 0.75 toapproximately 2.8, or wherein x may range from approximately 0.8 toapproximately 2.5, or wherein x may range from 0.9 to approximately 2.3,or alternatively wherein x may range from approximately 0.95 toapproximately 2.2. The elemental composition ranges for ZrS_(x) maycomprise Zr from about 30 atomic % to about 60 atomic %, or from about35 atomic % to about 55 atomic %, or even from about 40 atomic % toabout 50 atomic %. Alternatively the elemental composition ranges forZrS_(x) may comprise S from about 25 atomic % to about 75 atomic %, or Sfrom about 30 atomic % to about 60 atomic %, or even S from about 35atomic % to about 55 atomic %.

In additional embodiments, the transition metal chalcogenide films ofthe present disclosure may comprise, less than about 20 atomic % oxygen,or less than about 10 atomic % oxygen, or less than about 5 atomic %oxygen, or even less than about 2 atomic % oxygen. In furtherembodiments, the transition metal chalcogenide films may comprise, lessthan about 25 atomic % hydrogen, or less than about 10 atomic %hydrogen, or less than about 5 atomic % of hydrogen, or less than about2 atomic % of hydrogen, or even less than about 1 atomic % of hydrogen.In yet further embodiments, the transition metal chalcogenide films maycomprise, less than about 20 atomic % carbon, or less than about 10atomic % carbon, or less than about 5 atomic % carbon, or less thanabout 2 atomic % carbon, or less than about 1 atomic % of carbon, oreven less than about 0.5 atomic % carbon. In the embodiments outlinedherein, the atomic concentration of an element may be determinedutilizing Rutherford backscattering (RBS) and/or elastic recoildetection analysis (ERDA).

In some embodiments of the disclosure, the transition metal chalcogenidefilms may be deposited on a three-dimensional structure. In someembodiments, the step coverage of the transition metal chalcogenidefilms may be equal to or greater than about 50%, or greater than about80%, or greater than about 90%, or about 95%, or about 98%, or about 99%or greater in structures having aspect ratios (height/width) of morethan about 2, more than about 5, more than about 10, more than about 25,more than about 50, or even more than about 100.

In some embodiments, the transition metal chalcogenide film of thepresent disclosure, such as hafnium and zirconium dichalcogenide films,may be deposited to a thickness from about 20 nanometers to about 100nanometers. In some embodiments, a transition metal chalcogenide thinfilm deposited according to some of the embodiments described herein mayhave a thickness from about 20 nanometers to about 60 nanometers. Insome embodiments, a transition metal chalcogenide thin film depositedaccording to some of the embodiments described herein may have athickness greater than about 20 nanometers, or greater than about 30nanometers, or greater than about 40 nanometers, or greater than about50 nanometers, or greater than about 60 nanometers, or greater thanabout 100 nanometers, or greater than about 250 nanometers, or greaterthan about 500 nanometers, or even greater. In some embodiments atransition metal chalcogenide thin film deposited according to some ofthe embodiments described herein may have a thickness of less than about50 nanometers, or less than about 30 nanometers, or less than about 20nanometers, or less than about 15 nanometers, or less than about 10nanometers, or less than about 5 nanometers, or less than about 3nanometers, or less than about 2 nanometers, or less than about 1.5nanometers, or even less than about 1 nanometer.

In some embodiments a transition metal chalcogenide film, such as ahafnium or zirconium dichalcogenide film deposited according to some ofthe embodiments described herein may have a thickness of equal to orless than about 10 monolayers of transition metal chalcogenide material,or equal to or less than about 7 monolayers of transition metalchalcogenide material, or equal to or less than about 5 monolayers oftransition metal chalcogenide material, or to equal or less than about 4monolayers of transition metal chalcogenide material, or equal to orless than about 3 monolayers of transition metal chalcogenide material,or equal to or less than about 2 monolayers of transition metalchalcogenide material, or even equal to or less than about 1 monolayerof transition metal chalcogenide material.

In some embodiments of the disclosure, the transition metal chalcogenidefilms deposited according the methods disclosed herein may include aprotective capping layer to substantially prevent, or even prevent, theunwanted oxidation of the transition metal chalcogenide film. Forexample, upon completion of the deposition of the transition metalchalcogenide the chalcogenide film may be unloaded from the reactionchamber and exposed to ambient conditions wherein oxygen and/or waterwithin the ambient environment may oxidize the deposited transitionmetal chalcogenide film.

Therefore, in some embodiments, a capping layer may be deposited overthe transition metal chalcogenide film and particularly depositeddirectly over the transition metal chalcogenide film. In addition, toprevent any potential oxidation of the transition metal chalcogenidefilm, the capping layer may be deposited within the same reactionchamber utilized to deposit the transition metal chalcogenide, i.e., thecapping layer may be deposited in-situ within the same reaction chamberutilized to deposit the transition metal chalcogenide film. Therefore,in some embodiments of the disclosure, the methods may further comprise,in-situ depositing a capping layer over the transition metalchalcogenide film to substantially prevent oxidation of the transitionmetal chalcogenide film when exposed to ambient conditions.

In some embodiments, the capping layer may comprise a metal silicatefilm. In some embodiments, the metal silicate film may comprise at leastone of an aluminum silicate (Al_(x)Si_(y)O_(x)), a hafnium silicate(Hf_(x)Si_(y)O_(x)), or a zirconium silicate (Zr_(x)Si_(y)O_(x)). Moredetailed information regarding the deposition of metal silicate filmsmay be found in U.S. Pat. No. 6,632,279, filed on Oct. 13, 2000, titled“METHOD FOR GROWING THIN OXIDE FILMS,” all of which is herebyincorporated by reference and made a part of this specification.

In some embodiments, the capping layer may be deposited directly on thetransition metal chalcogenide film by a cyclical deposition process,such as an atomic layer deposition process, or a cyclical chemical vapordeposition process, as disclosed herein previously. As a non-limitingexample, the capping layer may comprise a metal silicate and the metalsilicate may be deposited by cyclical deposition process, such as atomiclayer deposition, for example. In some embodiments, the capping layermay be deposited using processes comprising non-oxidativereactants/precursors, or non-oxygen reactants (for example without O₂,H₂O, O₃, H₂O₂, O-containing plasmas, radicals or atoms) containingprocesses. Therefore, in some embodiments, the capping layer may bedeposited without utilizing H₂O, O₃, or H₂O₂. In some embodiments, thecapping layer may be deposited without utilizing an oxygen based plasma,i.e., without 0-containing plasmas, oxygen radicals, oxygen atoms, oroxygen excited species. The capping layer may be deposited usingprocesses comprising non-oxidative reactants/precursor, or non-oxygenreactants to prevent, or substantially prevent, the oxidation of theunderlying transition metal chalcogenide film. Therefore, in someembodiments, in-situ depositing a capping layer over the transitionmetal chalcogenide film may be performed without additional oxidation ofthe transition metal chalcogenide film.

In other embodiments, the capping layer may comprise a metal, such as atransition metal, for example. In some embodiments, the capping layermay comprise, a nitride, a sulfide, a carbide, or mixtures thereof, orfor example a silicon containing layer such as an amorphous siliconlayer. In other embodiments, the capping layer can be a dielectriclayer. In other embodiments, the capping layer can be a conductivelayer. In other embodiments, the capping layer can be a semiconductorlayer.

An exemplary ALD process for depositing the capping layer may compriseone or more repeated unit deposition cycles, wherein a unit depositioncycle may comprise, contacting the substrate with a metal vapor phasereactant, purging the reaction chamber of excess metal precursor andreaction by-products, contacting the substrate with a precursorcomprising both a silicon component and an oxygen component, and purgingthe reaction chamber for a second time. As a non-limiting example, thecapping layer may comprise an aluminum silicate film (Al_(x)Si_(y)O_(z))and the metal vapor phase reactant may comprise aluminum trichloride(AlCl₃) whereas the precursor comprising both a silicon component and anoxygen component may comprise tetra-n-butoxysilane Si(O^(n)Bu)₄. In someembodiments of the disclosure, the capping layer may comprise a metalsilicate deposited without the use of an oxidizing precursor, such as,for example, O₂, H₂O, O₃, H₂O₂, O-containing plasmas, radicals or atoms.

In some embodiments, the capping layer may be deposited at the sametemperature utilized to deposit the transition metal chalcogenide film.For example, the capping layer may be deposited at a temperature of lessthan 500° C., or less than 450° C., or less than 400° C., or less than300° C., or less than 200° C. In some embodiments, the capping layer maybe deposited at a temperature between approximately 200° C. and 500° C.,and particularly at a deposition temperature of approximately 400° C.

In some embodiments, the capping layer may be deposited to a thicknessof less than 50 nanometers, or less than 40 nanometers, or less than 30nanometers, or less than 20 nanometers, or less than 10 nanometers, orless than 7 nanometers, or less than 5 nanometers, or less than 3nanometers, or less than 2 nanometers, or even less than 1 nanometer. Insome embodiments, the capping layer is a continuous film and is disposeddirectly over the metal chalcogenide film to substantially preventoxidation of the metal chalcogenide film.

As a non-limiting example, FIG. 6 illustrates the ambient stability overtime of both a bare zirconium chalcogenide film and a zirconiumchalcogenide film capped with an aluminum silicate capping layerdeposited according to the embodiments of the disclosure. In moredetail, FIG. 6 illustrates the change in the normalized x-raydiffraction (XRD) intensity of the primary (001) peak over exposure timeto ambient conditions for both an aluminum silicate capped zirconiumdisulfide film (represented by the triangular data markers) and anuncapped, bare zirconium disulfide film (represented by the square datamarks). Examination of the data for the bare zirconium disulfide filmillustrates that the intensity of the (001) peak in the XRD datadecreases over time indicating the bare zirconium disulfide oxidizesover the time exposed to the ambient conditions. In contrast,examination of the data for the aluminum silicate capped zirconiumdisulfide film illustrates no decrease in the intensity of the (001)peak in the XRD data over time, indicating substantially no oxidation ofthe capped zirconium disulfide film.

In some embodiments of the disclosure, the in-situ deposition of thecapping layer directly on the surface of the transition metalchalcogenide film may be beneficial in improving the quality of thintransition metal chalcogenide films as the capping layer may preventoxidation of the chalcogenide film during reaction chamber cool downafter the deposition.

In more detail, FIG. 7A illustrates grazing incidence x-ray diffraction(GIXRD) data for exemplary zirconium disulfide films deposited utilizinga different number of deposition cycles without a capping layer and FIG.7B illustrates grazing incidence x-ray diffraction (GIXRD) data forexemplary zirconium chalcogenide films deposited utilizing a differentnumber of deposition cycles with an in-situ capping layer depositeddirectly over the chalcogenide film. Examination of FIG. 7A, i.e., theuncapped zirconium disulfide, illustrates that the XRD peakcorresponding to crystalline zirconium disulfide does not appear until1000 deposition cycle have been completed, which corresponds to athickness of approximately 8 nanometers. In contrast, examination ofFIG. 7B, i.e., the capped zirconium disulfide, illustrates that the XRDpeak corresponding to crystalline zirconium disulfide appears at 500deposition cycles, which corresponds to a thickness of approximately 4nanometers. Therefore, in some embodiments of the disclosure, the metalchalcogenide film may be covered by an in-situ capping layer and themetal chalcogenide film may be crystalline below a thickness of lessthan approximately 5 nanometers, or less than approximately 4nanometers, or less than approximately 2 nanometers, or less than 1.5nanometers, or even less than 1 nanometer.

The metal chalcogenide films deposited by the cyclical depositionprocesses disclosed herein may be utilized in a variety of contexts,such as in the formation of semiconductor device structures. One ofskill in the art will recognize that the processes described herein areapplicable to many contexts, including, but not limited to, thefabrication of transistors.

As a non-limiting example, and with reference to FIG. 8, a semiconductordevice structure 800 may comprise a field effect transistor (FET) whichmay include a silicon substrate 802 and a silicon dioxide (SiO₂) layer804 disposed over the silicon substrate 802. The semiconductor devicestructure 800 may further comprise a source region 806 and a drainregion 808. Disposed between the source and drain regions is atransition metal chalcogenide film 810 deposited according to theembodiments of the disclosure. The transition metal chalcogenide film810 may comprise a film of hafnium disulfide or zirconium disulfide andmay consist of the channel region of the FET structure. In someembodiments of the disclosure, the transition metal chalcogenide film810 may have thickness of less than 10 nanometers, or less than 5nanometers, or even less than 1 nanometer. Disposed directly over thetransition metal chalcogenide film 810 may be a capping layer 811. Forexample, the capping layer 811 may comprise a metal silicate film and inparticular an aluminum silicate film. The semiconductor device structure800 may further comprise a gate dielectric layer 812 disposed over thetransition metal chalcogenide film 810, wherein the gate dielectriclayer 812 may comprise hafnium dioxide (HfO₂). The semiconductor devicestructure 800 may further comprise a gate electrode 814 disposed overthe transition metal chalcogenide film 810.

Embodiments of the disclosure may also include a reaction systemconfigured for depositing the transition metal chalcogenide films of thepresent disclosure. In more detail, FIG. 9 schematically illustrates areaction system 900 including a reaction chamber 902 that furtherincludes mechanism for retaining a substrate (not shown) underpredetermined pressure, temperature, and ambient conditions, and forselectively exposing the substrate to various gases. A precursorreactant source 904 may be coupled by conduits or other appropriatemeans 904A to the reaction chamber 902, and may further couple to amanifold, valve control system, mass flow control system, or mechanismto control a gaseous precursor originating from the precursor reactantsource 904. A precursor (not shown) supplied by the precursor reactantsource 904, the reactant (not shown), may be liquid or solid under roomtemperature and standard atmospheric pressure conditions. Such aprecursor may be vaporized within a reactant source vacuum vessel, whichmay be maintained at or above a vaporizing temperature within aprecursor source chamber. In such embodiments, the vaporized precursormay be transported with a carrier gas (e.g., an inactive or inert gas)and then fed into the reaction chamber 902 through conduit 904A. Inother embodiments, the precursor may be a vapor under standardconditions. In such embodiments, the precursor does not need to bevaporized and may not require a carrier gas. For example, in oneembodiment the precursor may be stored in a gas cylinder. The conduit904A may further comprise a gas purifier 905A for substantially removingunwanted contaminants from the vapor fed to the reaction chamber 902.

The reaction system 900 may also include additional precursor reactantsources, such as precursor reactant source 906 which may also be coupledto the reaction chamber 902 by mean of conduits 906A and additional gaspurifier 905B, as described above.

A purge gas source 908 may also be coupled to the reaction chamber 902via conduits 908A, and selectively supplies various inert or noble gasesto the reaction chamber 902 to assist with the removal of precursor gasor waste gasses from the reaction chamber. The various inert or noblegasses that may be supplied may originate from a solid, liquid or storedgaseous form.

The reaction system 900 of FIG. 9 may also comprise a system operationand control mechanism 910 that provides electronic circuitry andmechanical components to selectively operate valves, manifolds, pumpsand other equipment included in the reaction system 900. Such circuitryand components operate to introduce precursors, purge gasses from therespective precursor sources 904, 906, and purge gas source 908. Thesystem operation and control mechanism 910 also controls timing of gaspulse sequences, temperature of the substrate and reaction chamber, andpressure of the reaction chamber and various other operations necessaryto provide proper operation of the reaction system 900. The operationand control mechanism 910 can include control software and electricallyor pneumatically controlled valves to control flow of precursors,reactants and purge gasses into and out of the reaction chamber 902. Thecontrol system can include modules such as a software or hardwarecomponent, e.g., a FPGA or ASIC, which performs certain tasks. A modulecan advantageously be configured to reside on the addressable storagemedium of the control system and be configured to execute one or moreprocesses.

Those of skill in the relevant arts appreciate that other configurationsof the present reaction system are possible, including different numberand kind of precursor reactant sources and purge gas sources. Further,such persons will also appreciate that there are many arrangements ofvalves, conduits, precursor sources, purge gas sources that may be usedto accomplish the goal of selectively feeding gasses into reactionchamber 902. Further, as a schematic representation of a reactionsystem, many components have been omitted for simplicity ofillustration, and such components may include, for example, variousvalves, manifolds, purifiers, heaters, containers, vents, and/orbypasses.

The example embodiments of the disclosure described above do not limitthe scope of the invention, since these embodiments are merely examplesof the embodiments of the invention, which is defined by the appendedclaims and their legal equivalents. Any equivalent embodiments areintended to be within the scope of this invention. Indeed, variousmodifications of the disclosure, in addition to those shown anddescribed herein, such as alternative useful combination of the elementsdescribed, may become apparent to those skilled in the art from thedescription. Such modifications and embodiments are also intended tofall within the scope of the appended claims.

What is claimed is:
 1. A reaction system comprising: a reaction chamber;a first precursor reactant source comprising at least one transitionmetal containing reactant comprising at least one of a hafnium precursorand a zirconium precursor; a second precursor reactant source comprisingat least one chalcogen containing reactant; and a system operation andcontrol mechanism, wherein the system operation and control mechanismcontrols timing of gas pulse sequences from the first precursor reactantsource and the second precursor reactant source to: contact a substratewith a vapor phase of the at least one transition metal containingreactant; and contact the substrate with a vapor phase of the at leastone chalcogen containing reactant, to thereby form a transition metalchalcogenide film by a cyclical deposition process, wherein thetemperature of the substrate during the steps of contact the substratewith a vapor phase of the at least one transition metal containingreactant and contact the substrate with a vapor phase of the at leastone chalcogen containing vapor phase reactant is below 450° C.
 2. Thereaction system of claim 1, wherein the cyclical deposition processcomprises an atomic layer deposition process.
 3. The reaction system ofclaim 1, wherein the cyclical deposition process comprises a cyclicalchemical vapor deposition process.
 4. The reaction system of claim 1,wherein the first precursor reactant source comprises at least one of ahalide precursor and a metalorganic precursor.
 5. The reaction system ofclaim 4, wherein the first precursor reactant source comprises at leastone of hafnium tetrachloride (HfCl₄) and zirconium tetrachloride(ZrCl₄).
 6. The reaction system of claim 4, wherein the metalorganicprecursor comprises at least one of an alkylamide precursor and acyclopentadienyl-ligand containing precursor.
 7. The reaction system ofclaim 6, wherein the alkylamide precursor comprises at least one oftetrakis(ethylmethylamido)hafnium (Hf(NEtMe)₄) andtetrakis(ethylmethylamido)zirconium (Zr(NEtMe)₄).
 8. The reaction systemof claim 6, wherein the cyclopentadienyl-ligand containing precursorcomprises at least one of tris(dimethylamido)cyclopentadienylhafnium(HfCp(NMe₂)₃), bis(methylcyclopentadienyl)methoxymethylhafnium((MeCp)₂Hf(CH)₃(OCH₃)), tris(dimethylamido)cyclopentadienylzirconium(ZrCp(NMe₂)₃), and bis(methylcyclopentadienyl)methoxymethylzirconium((MeCp)₂Zr(CH)₃(OCH₃)).
 9. The reaction system of claim 1, wherein theat least one chalcogen containing reactant comprises hydrogen sulfide(H₂S), hydrogen selenide (H₂Se), dimethyl sulfide ((CH₃)₂S), or dimethyltelluride (CH₃)₂Te.
 10. The reaction system of claim 1, furthercomprising a gas purifier, wherein the system operation and controlmechanism further controls a flow of the vapor phase of the at least onechalcogen containing reactant through the gas purifier prior to enteringthe reaction chamber to reduce a concentration of at least one of waterand oxygen within the vapor phase of the at least one chalcogencontaining reactant.
 11. The reaction system of claim 10, wherein theconcentration of at least one of water and oxygen within the chalcogencontaining vapor phase reactant is reduced to less than 1 part permillion.
 12. The reaction system of claim 1, wherein the systemoperation and control mechanism controls flow of a carrier gas throughthe first precursor reactant source to transport the vapor phase of theat least one transition metal containing reactant to the reactionchamber and to flow the carrier gas through a gas purifier prior toentering the first precursor reactant source to reduce a concentrationof at least one of water and oxygen within the carrier gas.
 13. Thereaction system of claim 12, wherein the concentration of at least oneof water and oxygen within the carrier gas is reduced to less than 1part per million.
 14. The reaction system of claim 1, wherein the systemoperation and control mechanism effectuates pre-anneal in the reactionchamber, prior to film deposition, at a temperature of greater than 500°C.
 15. The reaction system of claim 1, wherein the transition metalchalcogenide film comprises a predominant (001) crystallographicorientation.
 16. The reaction system of claim 1, wherein the systemoperation and control mechanism further effectuates deposition of acapping layer over the transition metal chalcogenide film tosubstantially prevent oxidation of the transition metal chalcogenidefilm when exposed to ambient conditions.
 17. The reaction system ofclaim 16, wherein the depositing the capping layer over the transitionmetal chalcogenide film comprises depositing the capping layer utilizingnon-oxidative precursors or non-oxygen reactants.
 18. The reactionsystem of claim 16, wherein the capping layer comprises a metal silicatefilm.
 19. The reaction system of claim 16, wherein the metal silicatefilm comprises an aluminum silicate film.
 20. The reaction system ofclaim 1, wherein the operation and control mechanism controls a pressurewithin the reaction chamber.